first according to AMD Forum rules: INFORMATION REQUIRED WHEN POSTING A QUESTION .
What is showing under Control Panel - Sound?
Whatever you have hooked up to the GPU card will probably be the "default' Audio device under AMD HD AUDIO.
Click on the Audio Device you want and choose "Default Audio Device" . You then should hear sound. Test the speakers in Sound Panel under "Configure" and run "TEST". you should hear some audio short sounds in each speaker.